Is it really a vast improvement when you punched out your bike to a 420? Was the real benefit distributed around the entire rev range or was it specific?

I was actually thinking of doing this. Gary at WB told me to bring down my stock head and he would swap it for a 420 head with all the bits and pieces and a really good price. I dont remeber the figure, i will have to call him tomorrow to find out.



I have not punched mine out to a 417cc yet but I'm thinking seriously about it.


It is very tempting isn't it.....

The last time I spoke to Gary about the 420 kit was about 2 months ago. His feedback was great. The initial teathing problems they had were resolved the the upgrade is VERY stable and relaible. They have been racing the 420 kits for about 12 months and have had no problems...

I will speak to him tomorrow and get some additional feedback.


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